-
The present invention relates to identifying video and/or audio material. The
invention also relates to a method of, and apparatus for, identifying video and/or audio
material and/or data.
-
The following discussion refers to video for convenience. The invention is not
limited to video: it may be applied to audio. It may be applied to data other than video
and audio. It may be applied to any one or more of video, audio and data. "Material"
as used herein refers to any one or more of video, audio and other data.
-
It is known to identify the ownership of video material by applying a
"watermark" to the video signal. A watermark may also, or alternatively identify a
distributor of the material. A watermark is a coded signal, which is combined with the
video signal in such a way that the coded signal is invisible or substantially invisible in
the displayed image. The coded signal is detectable in the video signal: it is used for
detecting infringement of copyright for example.
-
According to one aspect of the present invention, there is provided a method of
identifying material comprising the step of inserting an identifying code into the
material as a watermark, which code directly or indirectly identifies the material.
-
According to another aspect of the invention, there is provided apparatus
comprising a code generator for generating a code which directly or indirectly
identifies material, and a watermark generator for generating, from the code, a
watermark and for combining the watermark with the material.
-
Thus instead of identifying the ownership or distributor, the present invention
uses the watermark to directly or indirectly identify the material. This allows other
metadata relating to the material to be directly or indirectly linked to the material.
Examples of such metadata include technical metadata and descriptive metadata. An
example of descriptive metadata is the title of the material. In the case of video
material, an example of technical metadata is data concerning camera aspect ratio.
The metadata may be stored in a database, separate from the recording medium
carrying the material, and the identifying code in the watermark links the material to
the database.
-
By providing the identifying code in the watermark in the signal, the material
retains its identification throughout the production and distribution chain following the
provision of the code. This also avoids the necessity of a separate channel such as a
separate tape track for the identifying code. That makes easier subsequent material
processing with retention of the identifying code in association with the material.
-
In one embodiment of the invention, the material is recorded on an example of
a recording medium and the identifying code is a code identifying the example of the
recording medium. The identifying code may be, for example, a serial number. By
way illustration, CDs may be given serial numbers, each CD being an example of a
recording medium. The identifying code may be used to refer to a UMID, a unique
material identifier thus indirectly identifying the material.
-
In embodiments of the invention, the code is inserted into the signal or
recorded with the signal in addition to being in the watermark. For example, the code
may be in user bits of vertical interval time code and/or linear time code of video
material.
-
In another embodiment, the code is a UMID thus directly identifying the
material. UMIDs may be used to identify video, audio and data material.
-
A UMID allows unique linking of the material metadata stored in a database.
-
In an embodiment in which the code is a UMID, the instance number of the
UMID is used to provide in a plurality of copies of a piece of material respective
UMIDs and thus watermarks which are unique to individual users or groups of users in
addition to identifying the material.
-
For a better understanding of the present invention, reference will now be made
by way of example to the accompanying drawings in which:
- Figure 1 is a schematic diagram of an illustrative video material processing
system embodying the present invention;
- Figure 2 illustrates a basic and extended UMID;
- Figure 3 illustrates a reduced data structure;
- Figure 4 is a schematic block diagram of an illustrative spatial domain
watermarking system;
- Figure 5 is a schematic block diagram of an illustrative frequency domain
watermarking system;
- Figure 6 illustrates a data structure of a metadata base;
- Figures 7 to 9 illustrate the use of Linear Time Codes;
- Figure 10 is a block diagram of an illustrative watermark inserter;
- Figure 11 is a block diagram of an illustrative UMID detector; and
- Figure 12 is a block of a system for removing a watermark from a watermarked
image.
-
-
The following description illustrates the invention by way of reference to
identifying video material. However, the invention is not limited to video material.
Overview
-
Referring to Figure 1, UMIDs are generated by a generator 701. UMIDs are
described in the section UMIDs below. A UMID universally uniquely identifies video
and/or audio, and/or other data material as will be described below. Video material is
generated by a source 703. The source may be any video source known in the art,
including a camera, a VTR, a disc recorder/reproducer, and a video server amongst
other sources. In accordance with an embodiment of the present invention, a basic
UMID is inserted as a watermark, by a watermark inserter 705, into every frame of
the video material. Examples of inserters 705 are described in the section
Watermarking below.
-
The watermarked video material is utilised in a utiliser 717. The utiliser 717
may be a transmission, or other distribution, chain, a video processor for example an
editor, or a video store amongst other possibilities.
-
One or more watermark detectors 707 is/are provided for detecting the
watermark in the material. The detectors may be provided in the utiliser 717, or in the
transmission or distribution chain, or elsewhere in a video production and distribution
system.
-
The UMID in the material uniquely links the material to metadata in a database
processor 709. Metadata which may be included in the database is described in the
section Metadata below.
-
By detecting the watermark and extracting therefrom the UMID using the
detector 709, the metadata relevant to the material may be accessed. Metadata may be
provided in the database by means symbolically shown at 711. Such means may be a
keyboard and/or one or more communication links via which metadata is provided
from one or more sources (not shown).
-
Using the basic UMID allows access to the metadata relating to the material.
By putting the UMID in the video material as a watermark the need for a separate
channel, such as a separate track in a tape, is avoided. If the watermark is robust, then
it will survive processing e.g. editing or special effects, and/or transmission and/or
distribution and so maintain the link with the metadata.
-
An embodiment of the invention uses an extended UMID. An extended UMID
allows the identification of the owner of the material by virtue of the Country,
Organisation and User bytes. Also, an extended UMID has a Time/Date field which
may include video field time codes. Thus an extended UMID not only may be
provided in every frame but also may identify uniquely every frame by time codes and
may identify ownership of every frame. Video material is often produced by
combining clips which may have different owners. Thus the watermarks of this
embodiment of the invention allow identification of ownership to the accuracy of one
frame. Also the need for a separate channel is avoided and links to the associated
metadata are provided by the UMIDs. Details of ownership are preferably provided in
the database of processor 709.
Fingerprinting
-
A basic UMID has an Instance Number field which is used to distinguish
different instances of the same material. For example an original video clip is a first
instance of the material. A copy of it is a second instance. The instance number may
represent different representations of the same material. If say the first instance is
analogue then a digital compressed version of that is another instance.
-
In accordance with an embodiment of the invention, the instance number is
used to identify authorised users of the video material. For example, copies of original
video material owned by one organisation may be made available to other
organisations for distribution through different distribution channels or in different
markets or in different versions. Each organisation is identified by a code entered into
the instance number field of the basic UMID.
-
This requires a method of generating codes which are different from normal
instance numbers. (The SMPTE standard, current at the time of writing this patent
application, for generating instance numbers does not cover generating the codes of
this embodiment of the invention.) To avoid ambiguity, a central registry of Codes
and the organisations to which they refer may be provided by a database processor
referred to as Registry 715. An organisation requiring a code applies to the registry
which allocates a code. Alternatively, rules for generating the codes automatically by
the organisations may be provided. As another alternative, the codes may be
automatically generated by the organisations using random number generators to
minimise but not necessarily eliminate ambiguity. Preferably codes generated
automatically would be registered with the registry 715 after generation.
-
Thus the UMID as a watermark may be used to identify different authorised
users of video material. This is done to frame accuracy and if done using an extended
UMID also identifies the owner(s) of the video material.
-
In addition to providing the identifying code, preferably a UMID, in a
watermark, the code may also be in the signal. For example it may be in the vertical
blanking interval. It may be in the user bits of Linear Time Code (LTC) of a tape
and/or in the user bits of the Vertical Interval Time Code (VTIC). The Insertion into
LTC is described below in the section of that name.
-
Providing the identifying code in VITC or LTC may be advantageous when
processing the video material allowing the identifying code to be more easily and
simply accessed than by decoding it from the watermark.
UMIDs-Figures 2 and 3.
UMIDs
-
A UMID is described in SMPTE Journal, March 2000. Such a UMID is
referred to herein as the UMID of the SMPTE standard. Referring to Figure 2, an
extended UMID is shown. It comprises a first set of 32 bytes of basic UMID and a
second set of 32 bytes of signature metadata.
-
The first set of 32 bytes is the basic UMID. The components are:
- •A 12-byte Universal Label to identify this as a SMPTE UMID. It defines the
type of material which the UMID identifies and also defines the methods by which the
globally unique Material and locally unique Instance numbers are created.
- •A 1-byte length value to define the length of the remaining part of the UMID.
- •A 3-byte Instance number which is used to distinguish between different
'instances' of material with the same Material number.
- •A 16-byte Material number which is used to identify each clip. Each Material
number is the same for related instances of the same material.
-
-
The second set of 32 bytes of the signature metadata as a set of packed
metadata items used to create an extended UMID. The extended UMID comprises the
basic UMID followed immediately by signature metadata which comprises:
- •An 8-byte time/date code identifying the time and date of the Content Unit
creation.
- •A 12-byte value which defines the spatial co-ordinates at the time of Content
Unit creation.
- •3 groups of 4-byte codes which register the country, organisation and user
codes
-
-
Each component of the basic and extended UMIDs will now be defined in turn.
The 12-byte Universal Label
-
The first 12 bytes of the UMID provide identification of the UMID by the
registered string value defined in table 1.
-
The hex values in table 1 may be changed: the values given are examples.
Also the bytes 1-12 may have designations other than those shown by way of example
in the table. Referring to the Table 1, in the example shown byte 4 indicates that bytes
5-12 relate to a data format agreed by SMPTE. Byte 5 indicates that bytes 6 to 10
relate to "dictionary" data. Byte 6 indicates that such data is "metadata" defined by
bytes 7 to 10. Byte 7 indicates the part of the dictionary containing metadata defined
by bytes 9 and 10. Byte 10 indicates the version of the dictionary. Byte 9 indicates
the class of data and Byte 10 indicates a particular item in the class.
-
In the present embodiment bytes 1 to 10 have fixed preassigned values. Byte
11 is variable. Thus referring to Figure 3, and to Table 1 above, it will be noted that
the bytes 1 to 10 of the label of the UMID are fixed. Therefore they may be replaced
by a 1 byte 'Type' code T representing the bytes 1 to 10. The type code T is followed
by a length code L. That is followed by 2 bytes, one of which is byte 11 of Table 1
and the other of which is byte 12 of Table 1, an instance number (3 bytes) and a
material number (16 bytes). Optionally the material number may be followed by the
signature metadata of the extended UMID and/or other metadata.
-
The UMID type (byte 11) has 4 separate values to identify each of 4 different
data types as follows:
- '01h' = UMID for Picture material
- '02h' = UMID for Audio material
- '03h' = UMID for Data material
- '04h' = UMID for Group material (i.e. a combination of related essence).
-
-
The last (12th) byte of the 12 byte label identifies the methods by which the
material and instance numbers are created. This byte is divided into top and bottom
nibbles where the top nibble defines the method of Material number creation and the
bottom nibble defines the method of Instance number creation.
Length
-
The Length is a 1-byte number with the value '13h' for basic UMIDs and '33h'
for extended UMIDs.
Instance Number
-
The Instance number of the SMPTE standard is a unique 3-byte number which
is created by one of several means defined by the SMPTE standard. It provides a link
between a particular 'instance' of a clip and externally associated metadata. Without
this instance number, all material could be linked to any instance of the material and
its associated metadata.
-
The creation of a new clip requires the creation of a new Material number
together with a zero Instance number. Therefore, a non-zero Instance number
indicates that the associated clip is not the source material. An Instance number is
primarily used to identify associated metadata related to any particular instance of a
clip.
-
In accordance with an embodiment of the present invention, the instance
number of the SMPTE standard is modified. It is used to identify authorised users of
the material. Thus a code is used as a "fingerprint". The code may be generated as
described above in the section "Fingerprinting".
Material Number
-
The 16-byte Material number is a non-zero number created by one of several
means identified in the standard. The number is dependent on a 6-byte registered port
ID number, time and a random number generator.
Signature Metadata
-
Any component from the signature metadata may be null-filled where no
meaningful value can be entered. Any null-filled component is wholly null-filled to
clearly indicate a downstream decoder that the component is not valid.
The Time-Date Format
-
The date-time format is 8 bytes where the first 4 bytes are a UTC (Universal
Time Code) based time component. The time is defined either by an AES3 32-bit
audio sample clock or SMPTE 12M depending on the essence type.
-
The second 4 bytes define the date based on the Modified Julian Data (MJD) as
defined in SMPTE 309M. This counts up to 999,999 days after midnight on the 17th
November 1858 and allows dates to the year 4597.
The Spatial Co-ordinate Format
-
The spatial co-ordinate value consists of three components defined as follows:
- •Altitude: 8 decimal numbers specifying up to 99,999,999 metres.
- •Longitude: 8 decimal numbers specifying East/West 180.00000 degrees (5
decimal places active).
- •Latitude: 8 decimal numbers specifying North/South 90.00000 degrees (5
decimal places active).
-
-
The Altitude value is expressed as a value in metres from the centre of the earth
thus allowing altitudes below the sea level.
-
It should be noted that although spatial co-ordinates are static for most clips,
this is not true for all cases. Material captured from a moving source such as a camera
mounted on a vehicle may show changing spatial co-ordinate values.
Country Code
-
The Country code is an abbreviated 4-byte alpha-numeric string according to
the set defined in ISO 3166. Countries which are not registered can obtain a registered
alpha-numeric string from the SMPTE Registration Authority.
Organisation Code
-
The Organisation code is an abbreviated 4-byte alpha-numeric string registered
with SMPTE. Organisation codes have meaning only in relation to their registered
Country code so that Organisation codes can have the same value in different
countries.
User Code
-
The User code is a 4-byte alpha-numeric string assigned locally by each
organisation and is not globally registered. User codes are defined in relation to their
registered Organisation and Country codes so that User codes may have the same
value in different organisations and countries.
Freelance Operators
-
Freelance operators may use their country of domicile for the country code and
use the Organisation and User codes concatenated to e.g. an 8 byte code which can be
registered with SMPTE. These freelance codes may start with the '∼' symbol (ISO
8859 character number 7Eh) and followed by a registered 7 digit alphanumeric string.
-
It will be noted from the foregoing discussion that a UMID may be used to
identify not only video material, but also audio material, data material, and a group of
material.
Watermarking-Figures 4 and 5
-
Digital watermarking allows a code to be embedded in a digital work. The
digital watermark may be used in conjunction with other deterrents such as encryption.
-
In embodiments of the present invention, the watermark undetectable. It is
preferably unalterable and non-removable by unauthorised individuals. The
watermark preferably does not adversely degrade the underlying work in a manner that
is readily perceptible. In addition, the watermark is readily discernible by authorised
individuals.
-
The watermark may be placed in, for example, a header or label of a digital
work, or the watermark may be embedded within the data fields of the digital work
itself. Preferably, the watermark occurs many times within a work. For example it
may be present in every frame of a digital video work. Alternatively, the watermark
may be placed directly onto the media which carries the digital work.
-
The watermark may be robust such that it may not be removed or degraded by
individuals seeking to make unauthorised copies. Unauthorised attempts to remove the
robust watermark should result in severe degradation of the data, rendering the data
useless. Situations where the data contains much redundant information, such as in
video, may render the robust watermark susceptible to attack by, for example, frame
dropping or the like. Hence, the robust watermark should preferably withstand such
attacks and may, for example, change from frame to frame and may utilise any error
correction/recovery techniques which are applied to data.
-
Alternatively, the watermark may be fragile such that it is damaged should an
unauthorised copy be made. That enables detection of the unauthorised copy.
-
However, the watermark should also preferably be reversible and removable by
the owner, if required. Removal may be particularly useful during, for example, a
post-production stage to reduce any cumulative effects of the watermark on the
underlying work. Also, where information from different sources are edited together it
may be desired that a different watermark is applied to the edited product.
-
End-user equipment may be configured to recognise the watermark such that it
will not allow copying of protected works. Alternatively, the equipment may be
configured such that it will only play works originating from a particular owner,
distributed through a particular distributor or where the work contains a particular
authorisation code.
-
The watermark may be extracted by comparing watermarked with non-watermarked
data and its authenticity established.
-
Three techniques for imperceptibly embedding a watermark within the data
fields of a digital work will now be described in more detail. The first is to embed the
watermark in the spatial domain, the second is to embed the watermark in the
frequency domain, and the third is an example of the second. All of these embedding
processes are such that they do not result in a significant degradation of the data being
watermarked.
Spatial Domain Watermarks
-
The process, in overview, involves altering predetermined data bits with the
bits of a watermark to produce watermarked data. The existence of watermark may be
determined by performing the reverse operation on the watermarked data.
-
One approach is to embed a watermark by substituting insignificant bits of
pseudo-randomly selected data with bits representing the watermark. However, these
watermarks are susceptible to destruction by processing the least significant bits of the
data. Another is to insert geometric patterns into the data which represent a
watermark. However, these watermarks are susceptible destruction by geometric
processing of the data. A further approach is to embed a watermark in a manner which
resembles quantisation noise as described with reference to Figure 4 below and more
fully described in articles titled "Embedding Secret Information into a Dithered Multi-Level
Image" by K Tanaka et al, IEEE Military Communications Conference pages
216-220, 1990 and "Video Steganography" by K Mitsui, IMA Intellectual Property
Proceedings, volume 1, pages 187-296, 1994. However, these watermarks are
susceptible destruction by signal processing, particularly by requantisation of the data.
-
Referring now to Figure 4, a source 650 produces a digital data signal 652,
such as digital video. A watermark inserter 700 is couple to the source 650 and
receives the digital data signal 652. The watermark inserter 700 applies the watermark
663 by applying the watermark to the digital data signal 652 in a manner that resemble
requantisation noise to produce watermarked data 705. A storage device 670 is
coupled to the watermark inserter 700 and stores the watermarked data 705.
-
A yet further approach is to randomly select n pairs of image points (ai, bi) and
increase the brightness of ai by one while decreasing the brightness of bi by one.
Assuming certain statistical properties of the image are satisfied, the sum of the
differences of the n pairs of points will be 2n.
-
Alternatively, where the data signal comprises at least two components (for
example [Y, UV] according to MPEG, PAL or NTSC), the watermark may be
embedded by assigning values to these components which, in combination, do not
usually occur. Also, where a watermark is to be embedded in, for example, video data
containing two image fields, a positive watermark may be placed into the first field
and a negative watermark into the second field. When watermarked image fields are
played there is a masking effect due to the interlacing of the fields and the visual
perception of the watermark is significantly reduced.
Frequency Domain Watermarks
-
The process, in overview, involves obtaining a frequency spectral image of the
data to which the watermark is to be applied. The watermark is embedded into
predetermined components of the frequency spectral image. Thereafter, the
watermarked frequency spectral image is subjected to an inverse transform to produce
watermarked data. The watermark may be extracted by performing the reverse
operation on the watermarked data.
-
One approach is to partition the data into blocks and compute the Discrete
Cosine Transform (DCT) of each of these blocks. Thereafter, the predetermined
frequency coefficients of the blocks may be adjusted. A pseudo random subset of
blocks may be chosen and in each such block coefficients of predetermined subset of
frequencies adjusted such that their relative values encode a data bit. The variance in
the relative values and the selection of the predetermined subset of frequencies should
be such that the watermark is not perceptible. However, this watermark may be
sensitive to damage by noise or further processing.
-
Alternatively, the watermark may be encoded by adjusting every frequency
coefficient by a smaller amount as described with reference to Figure 5 below and
more fully described in European Patent Application 0 766 468, NEC Corporation.
This has the advantage of making the watermark less sensitive to damage, but
increases overall noise levels.
-
Referring now to Figure 5, a source 650 produces a digital data signal 652,
such as digital video. A frequency transformer 655 is coupled to the source 650 and
receives the digital data signal 652. The frequency transformer 655 transforms the
digital data signal 652 into frequency spectral data 657 using, for example, Discrete
Cosine Transforms or Fast Fourier Transform techniques. A watermark inserter 660 is
couple to the frequency transformer and receives the frequency spectral data 657. The
watermark inserter applies the watermark 663 by adjusting each coefficient of the
frequency spectral data 657 to produce watermarked frequency spectral data 663. An
inverse frequency transformer 665 is coupled to the watermark inserter 660 and
receives the watermarked frequency spectral data 663. The inverse frequency
transformer 665 converts the watermarked frequency spectral data 663 into
watermarked data 667. A storage device 670 is coupled to the inverse frequency
transformer 665 and stores the watermarked data 667.
-
A further approach is to increase the changes to coefficients in particular
frequencies by exploiting the existence of so-called masking phenomena in the human
visual and auditory systems. Masking occurs when certain regions of data are
occluded by perceptually more prominent regions elsewhere in the data. However,
these regions need to be identified prior to inserting the watermark which increases the
embedding complexity.
-
A yet further approach is to compress the digital data and embed the watermark
into the x and y co-ordinates of motion vectors of the compressed data. This has the
advantage of the watermark being embedded after compression and, hence, is more
robust to processing.
-
A currently preferred embodiment of a watermark inserter is shown in Figure
10, and a currently preferred UMID detector is shown in Figure 11.
-
Figure 10 illustrates the watermark embedder 120. The watermark embedder
120 comprises a pseudo-random sequence generator 220, an error correction coding
generator 200, a wavelet transformer 210, an inverse wavelet transformer 250, a first
combiner 230 and second combiner 240.
-
The error correction coding generator 200 receives a UMID 175 and outputs an
error correction coded UMID 205 to the first combiner 230. The pseudo-random
sequence generator 220 outputs a pseudo-random sequence 225 to the combiner 230.
The first combiner 230 receives the error correction coded UMID 205 from the error
correction coding generator 200, the pseudo-random sequence 225 from the pseudo-random
sequence generator 220 and outputs a watermark comprising a sequence of
bits Wi to the second combiner 240. The wavelet transformer 210 receives a video
image 115 from the source 110 and outputs a wavelet image X'i (comprising wavelet
coefficients X'i where X'i is the ith wavelet coefficient of the transformed image to
which bit Wi of the watermark is applied) to the second combiner 240. The second
combiner 240 receives the watermark Wi from the first combiner 230, the wavelet
image Xi from the wavelet transformer 210, a watermark strength coefficient a from
the strength adapter 180 and outputs a watermarked wavelet image X'i = Xi+αWi
where X'i is the ith watermarked coefficient. The watermarked wavelet image Xi is
applied to the inverse wavelet transformer 250. The inverse wavelet transformer 250
receives the watermarked wavelet image Xi and outputs a watermarked image 125.
-
The operation of the embedder 120 will now be described in more detail. In
overview, a UMID 175 associated with an video image 115 is processed to provide
error correction coded UMID 205 and thereafter combined with the pseudo-random
sequence 225 to produce a spectrum signal spread spectrum signal which is used as the
watermark Wi. A video image 115 is transformed into a wavelet image Xi and
thereafter the watermark 235 is applied in combiner 240 to produce the watermarked
wavelet image 245. The watermarked wavelet image 245 is then transformed to
produce a watermarked image 125.
-
The use of error correction coding to produce an error correction coded UMID
205 is advantageous since it allows the UMID 175 to be reconstructed more readily
should some information be lost. This provides a degree of robustness to future
processing or attacks against the watermark. The use of a pseudo-random sequence
225 to generate a spread spectrum signal for use as a watermark 235 is advantageous
since it allows the error correction coded UMID 205 to be spread across a larger
number of bits. Also, it allows the watermark Wi to be more effectively hidden.
Applying the watermark Wi to a wavelet image 215 is advantageous since this reduces
the perceptibility of the watermark. Furthermore, the strength α of the watermark 235
may be adjusted to ensure that the watermark 235 is not perceptible.
-
The operation of a watermark decoder 140 will now be explained in more
detail with reference to Figure 11. The watermark decoder 140 receives the
watermarked image 125 and outputs the UMID 175. The watermark decoder 140
comprises a wavelet transformer 310, a pseudo-random sequence generator 320, a
correlator 330, a selector 340 and a error correction coding decoder 350.
-
The wavelet transformer 310 receives the watermarked image 125 and, in
known manner, outputs a watermarked wavelet X'i. The correlator 330 receives a
pseudo-random sequence 325 from the pseudo-random sequence generator 320, the
watermarked wavelet 315 from the wavelet transformer 310 and outputs a watermark
image bit correlation sequence 335. The watermarked image bit correlation sequence
is determined in the following way. Each bit of the pseudo-random sequence 325 is
coded as follows, a "1" bit is coded as a "1" and a "0" bit is coded as a "-1". The
correlation value of each pixel of the selected portion of the watermarked wavelet 315
is calculated using the following equation:
Cn = i=1 s Xsn+iRi .
The watermarked image
bit correlation sequence 335 is received by the selector 340 which outputs an
uncorrected UMID 345. The selector 340 outputs a "1" for a watermarked image bit
correlation value greater than 0 and a bit value "0" for a image bit correlation value
less than or equal to 0. The error correction code decoder 350 receives the uncorrected
UMID 345 and in known manner outputs a restored UMID 175.
-
Figure 12, shows a system 130 for removal of the watermark for the
watermarked image. The removal system 130 receives the restored UMID 175, the
watermarked image 125 and outputs a restored image 135 from which the watermark
is removed. The system 130 comprises a pseudo-random sequence generator 420 for
generating a pseudo-random sequence 425, a spread spectrum signal generator 430 for
receiving a restored UMID 145 and the pseudo-random sequence 425 and for
producing a restored watermark 435. The system 130 further comprises: a wavelet
transformer 410 for receiving a watermarked image 125 and outputting watermarked
wavelet coefficients X'i; a watermark subtractor 440 which receives the bits Wi of the
restored watermark 435, the watermarked wavelet coefficients X'i; and a strength α.
The substractor outputs restored wavelet coefficients Xi to an inverse wavelet
transformer 450. The inverse wavelet transformer 450 outputs the restored image 135.
-
The watermark subtractor 440 codes a bit "1" of the restored watermark 435 as
a "1", and a bit "0" as a "-1". The watermark subtractor 440 applies the following
equation: X1 = X ' 1 - αnWi .
Metadata- Figure 6
-
The following is provided, by way of example, to illustrate the possible types
of metadata generated during the production of a programme, and one possible
organisational approach to structuring that metadata.
-
Figure 6 illustrates an example structure for organising metadata. A number of
tables each comprising a number of fields containing metadata are provided. The
tables may be associated with each other by way of common fields within the
respective tables, thereby providing a relational structure. Also, the structure may
comprise a number of instances of the same table to represent multiple instances of the
object that the table may represent. The fields may be formatted in a predetermined
manner. The size of the fields may also be predetermined. Example sizes include
"Int" which represents 2 bytes, "Long Int" which represents 4 bytes and "Double"
which represents 8 bytes. Alternatively, the size of the fields may be defined with
reference to the number of characters to be held within the field such as, for example,
8, 10, 16, 32, 128, and 255 characters.
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Turning to the structure in more detail, there is provided a Programme Table.
The Programme Table comprises a number of fields including Programme ID (PID),
Title, Working Title, Genre ID, Synopsis, Aspect Ratio, Director ID and Picturestamp.
Associated with the Programme Table is a Genre Table, a Keywords Table, a Script
Table, a People Table, a Schedule Table and a plurality of Media Object Tables.
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The Genre Table comprises a number of fields including Genre ID, which is
associated with the Genre ID field of the Programme Table, and Genre Description.
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The Keywords Table comprises a number of fields including Programme ID,
which is associated with the Programme ID field of the Programme Table, Keyword
ID and Keyword.
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The Script Table comprises a number of fields including Script ID, Script
Name, Script Type, Document Format, Path, Creation Date, Original Author, Version,
Last Modified, Modified By, PID associated with Programme ID and Notes. The
People Table comprises a number of fields including Image.
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The People Table is associated with a number of Individual Tables and a
number of Group Tables. Each Individual Table comprises a number of fields
including Image. Each Group Table comprises a number of fields including Image.
Each Individual Table is associated with either a Production Staff Table or a Cast
Table.
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The Production Staff Table comprises a number of fields including Production
Staff ID, Surname, Firstname, Contract ID, Agent, Agency ID, E-mail, Address, Phone
Number, Role ID, Notes, Allergies, DOB, National Insurance Number and Bank ID
and Picture Stamp.
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The Cast Table comprises a number of fields including Cast ID, Surname,
Firstname, Character Name, Contract ID, Agent, Agency ID, Equity Number, E-mail,
Address, Phone Number, DOB (date of birth) and Bank ID and Picture Stamp.
Associated with the Production Staff Table and Cast Table are a Bank Details Table
and an Agency Table.
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The Bank Details Table comprises a number of fields including Bank ID,
which is associated with the Bank ID field of the Production Staff Table and the Bank
ID field of the Cast Table, Sort Code, Account Number and Account Name.
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The Agency Table comprises a number of fields including Agency ID, which is
associated with the Agency ID field of the Production Staff Table and the Agency ID
field of the Cast Table, Name, Address, Phone Number, Web Site and E-mail and a
Picture Stamp. Also associated with the Production Staff Table is a Role Table.
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The Role Table comprises a number of fields including Role ID, which is
associated with the Role ID field of the Production Staff Table, Function and Notes
and a Picture Stamp. Each Group Table is associated with an Organisation Table.
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The Organisation Table comprises a number fields including Organisation ID,
Name, Type, Address, Contract ID, Contact Name, Contact Phone Number and Web
Site and a Picture Stamp.
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Each Media Object Table comprises a number of fields including Media Object
ID, Name, Description, Picturestamp, PID, Format, schedule ID, script ID and Master
ID. Associated with each Media Object Table is the People Table, a Master Table, a
Schedule Table, a Storyboard Table, a script table and a number of Shot Tables.
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The Master Table comprises a number of fields including Master ID, which is
associated with the Master ID field of the Media Object Table, Title, Basic UMID,
EDL ID, Tape ID and Duration and a Picture Stamp.
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The Schedule Table comprises a number of fields including Schedule ID,
Schedule Name, Document Format, Path, Creation Date, Original Author, Start Date,
End Date, Version, Last Modified, Modified By and Notes and PID which is
associated with the programme ID.
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The contract table contains: a contract ID which is associated with the contract
ID of the Production staff, cast, and organisation tables; commencement date, rate, job
title, expiry date and details.
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The Storyboard Table comprises a number of fields including Storyboard ID,
which is associated with the Storyboard ID of the shot Table, Description, Author,
Path and Media ID.
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Each Shot Table comprises a number of fields including Shot ID, PID, Media
ID, Title, Location ID, Notes, Picturestamp, script ID, schedule ID, and description.
Associated with each Shot Table is the People Table, the Schedule Table, script table,
a Location Table and a number of Take Tables.
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The Location Table comprises a number of fields including Location ID, which
is associated with the Location ID field of the Shot Table, GPS, Address, Description,
Name, Cost Per Hour, Directions, Contact Name, Contact Address and Contact Phone
Number and a Picture Stamp.
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Each Take Table comprises a number of fields including Basic UMID, Take
Number, Shot ID, Media ID, Timecode IN, Timecode OUT, Sign Metadata, Tape ID,
Camera ID, Head Hours, Videographer, IN Stamp, OUT Stamp. Lens ID, AUTOID
ingest ID and Notes. Associated with each Take Table is a Tape Table, a Task Table,
a Camera Table, a lens table, an ingest table and a number of Take Annotation Tables.
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The Ingest table contains an Ingest ID which is associated with the Ingest Id in
the take table and a description.
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The Tape Table comprises a number of fields including Tape ID, which is
associated with the Tape ID field of the Take Table, PID, Format, Max Duration, First
Usage, Max Erasures, Current Erasure, ETA ( estimated time of arrival) and Last
Erasure Date and a Picture Stamp.
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The Task Table comprises a number of fields including Task ID, PID, Media
ID, Shot ID, which are associated with the Media ID and Shot ID fields respectively of
the Take Table, Title, Task Notes, Distribution List and CC List. Associated with the
Task Table is a Planned Shot Table.
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The Planned Shot Table comprises a number of fields including Planned Shot
ID, PID, Media ID, Shot ID, which are associated with the PID, Media ID and Shot ID
respectively of the Task Table, Director, Shot Title, Location, Notes, Description,
Videographer, Due date, Programme title, media title Aspect Ratio and Format.
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The Camera Table comprises a number of fields including Camera ID, which is
associated with the Camera ID field of the Take Table, Manufacturer, Model, Format,
Serial Number, Head Hours, Lens ID, Notes, Contact Name, Contact Address and
Contact Phone Number and a Picture Stamp.
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The Lens Table comprises a number of fields including Lens ID, which is
associated with the Lens ID field of the Take Table, Manufacturer, Model, Serial
Number, Contact Name, Contact Address and Contact Phone Number and a Picture
Stamp.
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Each Take Annotation Table comprises a number of fields including Take
Annotation ID, Basic UMID, Timecode, Shutter Speed, Iris, Zoom, Gamma, Shot
Marker ID, Filter Wheel, Detail and Gain. Associated with each Take Annotation
Table is a Shot Marker Table.
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The Shot Marker Table comprises a number of fields including Shot Marker
ID, which is associated with the Shot Marker ID of the Take Annotation Table, and
Description.
Insertion into LTC -Figures 7 to 9
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Referring to Figure 7, a tape format is shown schematically. Video and audio
information is recorded in helical tracks of which a set of, e.g. 10 or 12, tracks records
one field of video. The helical tracks include vertical interval time codes (VITC). The
time codes may be duplicated in a linear time code track LTC, but the contents of the
VITC and LTC may be different. The tape may comprise at least one other linear
track (not shown). In this illustrative description it is assumed that all video, audio and
other information is recorded digitally. However, the video and audio may be
recorded as analogue information. The video and audio information may be
compressed according to the MPEG 2 standard for example.
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The time codes are recorded once per video field. As schematically shown in
Figure 8, a known time code has 80 bits of which 16 are reserved for synchronisation
information, 32 for time code bits and 32 for user defined bits, herein referred to as
"user bits". The user bits are interleaved with the other bits in a typical time code;
however the invention is not limited to that.
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The code, the UMID, is recorded in the user bits of the linear time code. If it
has 64 bits it occupies two time codes. It thus refers to one frame of two video fields.
In preferred embodiments the same code is repeated every frame. Preferably, the tape
is "prestriped" before use to record linear time codes for the fields.
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Referring to Figure 9, a UMID generator 701 generates a UMID and a material
source 703 provides in this example video material. The UMID and video material are
fed to a watermark generator 705 which inserts the UMID as a watermark into the
video. The watermarked video and the UMID from the generator are fed to a VTR 714
to record the UMID in the LTC and to record the watermarked video in the video
tracks.
Variants
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Instead of using a UMID, which is universally unique, another material
identifier could be used. For example, for material originally recorded on a record
medium, the identifier could be a serial number of a series thereof which identify the
media of an organisation, plus IN and OUT time codes of material on the medium.
That data could then be linked to for example a UMID in a database. Other material
identifiers could be used.
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Whilst the foregoing description, by way of example, illustrates the
invention by reference to video material, the invention may be applied to any
one or more of video material, audio material and data material.
